Current dollar amounts (see table 13-4b) were converted to chained 2000
dollars by the Bureau of Transportation Statistics to eliminate the effects
of inflation over time.

SOURCE: U.S. Department of Transportation, Bureau
of Transportation Statistics, calculations based on data from U.S. Department
of Commerce, Bureau of Economic Analysis, "Gross Domestic Product by
Industry," available at http://www.bea.gov/bea/dn2/gpo.htm, as of
February 2004.